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oct- 15, 1946-
. a ROSS ETAL
2,409,390
PROCESS FOR SIIULTAHEOUSLY ISOIERIZING AND SEPARATING
CYCLOPARAFFIHS PRO‘ AGYCLIC PARAFFINS BY MEANS
4
OF AN ALUIIHUI HALIDE-HYDROCARBON COMPLEX
Filed Dec. 4. 1944 V
A
Frac?omi
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37
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~lnvzn+brs= wiuims’ 5.2055
Philip Pezz-aq?a
Patented Oct. 15, 1946
2,409,390
UNITED STATES PATENT OFFICE
2,409,390
PROCESS FOR SIMULTANEOUSLY ISOMER
IZING AND SEPARATING CYCLOPARAF
FINS FROM ACYCLIC PARAFFINS BY
MEANS OF AN ALUMINUM HALIDE-HY
DROCARBON COMPLEX
William E. Ross, Berkeley, and Philip Pezzaglia,
Oakland, Calif., assignors to Shell Development
‘ Company, San Francisco, Calif.
Application December 4, 1944, Serial No. 566,538
10 Claims.
(01. 260-666)
1
2
This invention relates to an improved process
for the separation of cycloparaf?ns from hydro
carbon mixtures comprising cyclopara?ins in ad
the hydrocarbon, mixtures comprising open chain
paraflins and cycloparai?ns of non-hydroaroé
matic structure to isomerizing conditions eiiect
ing'the conversion of non-hydroaromatic cyclo
para?ins to hydroaromatic cycloparaf?ns and
mixture with open chain paraf?ns. The inven
tion relates more particularly to an improved
thereafter subject the entire hydrocarbon mix
ture to fractionation to separate fractions com
prising desired cyclopara?ins. Although such a
procedure enables the production on a practical
scale of certainof the, naphthenic hydrocarbons
such as, for example, cyclchexane in relatively
process for the production of cyclo-paraf?ns of
hydroaromatic structure from hydrocarbon mix
tures comprising openschain paraf?ns and cyclo
para?ins of non-hydroaromatic structure.
The cycloparaiiins have become of exceeding
‘importance as starting materials and interme
diates in the production of a wide variety of
organic products.
concentrated form it still does not enable the
attainment of desirable yields in even such sped
The most fertile source of
ci?c instances. Thus, in the production of cyclo
these highly desirable materials resides in the
‘hydrocarbon mixtures obtained in the natural 15 hexane from hydrocarbon mixtures such as naph
thenic gasolines as resorted to heretofore, the
state as petroleum, and in the products obtained
gasoline is generally ?rst fractionated to sep
in the thermal or catalytic treatment of petro
arate a methylcyclopentane fraction, thus leav
leum or distillate fractions thereof, and in the
ing the greater portion of cyclohexane and also
thermal or catalytic treatment such as, for ex
ample, hydrogenation of carbonaceous materials, 20 a considerable amount of methylcyclopentane in
a higher boiling fraction. Separation of such
etc. As is well known, the cycloparaf?ns in these
cyclohexane from the higher boiling hydrocarbon
readily available hydrocarbon mixtures are found
fraction by means such as simple distillation is
therein in admixture with open chain para?ins.
highly impractical due to the presence therein
Realization of the full advantages inherent in
the many chemical processes relying upon the‘ 25 of hydrocarbons such as, for example, dimethyl
cyclopara?ins as starting or intermediate mate
'pentanes boiling in the same range as cyclo
rials has heretofore been seriously handicapped
hexane.
subjection of the methylcyclopentane
fraction to isomerizing conditions under the con
by the lack of a process enabling the eflicient sep
ditions resorted to heretofore generally does not
aration on a practical scale of the cyclopara?'jns
‘from the open chain paraf?ns in admixture with 30 enable the attainment of a high conversion ap
Which they are generally encountered.
proaching equilibrium conversion of methylcyclo
Thus,
pentane to cyclohexane. Resort to the use of
separation of the cyclcparaflins from open chain
higher contact times though resulting in higher
paraf?ns having the same, or approximately the
conversion generally does not occasion a corre
same number of carbon atoms to the molecule,v
by such methods as fractional distillation if at 35 sponding increase in the quantity of cyclohexane
recovered due to a greater increase in the rate
all possible is often rendered so complex and
of undesirable side reactions‘ resulting in the con
delicate an operation as to render it highly im
version of both methylcyclopentane and cyclo
hexane to a higher boiling product.‘ After such
practical.
Of the cycloparaf?ns, those of hydroaromatic
structure are of particular value and ?nd appli 40 an iso-merization operation the highly vexing
problem of separating the naphthenic hydrocar
cation in the production of an exceedingly wide
bons from other hydrocarbons of close boiling
range of valuable organic products. The pro
duction of cycloparaf?ns of hydroaromatic struc
range admixed therewith remains. Thus, sep
aration from the cyclohexane produced of the
ture in a state of required purity is rendered
close boiling hydrocarbons such as dimethylpen
even more di?icult since, to the difficulty of their
,tanes,‘ generally encountered therewith, by meth
separation from open chain para?ins is added
the often equally vexing problem of their sep
aration from isomeric non-hydroaromatic cyclo
para?ins and other hydrocarbons of close boil
ing range or capable of forming azeotropes there
with. By the term “hydroaromatic cycloparaf
?ns” as used throughout this speci?cation and
appended claims is meant the cycloparamns hav
ing a hexamethylene ring such as, for example,
cyclohexane and the alkyl cyclohexanes, to dis
tinguish them from cyclop-ara?ins of non-hydro
aromatic structure comprising those having
pentamethylene rings such as. for example,
ods utilized heretofore is highly impractical. A
further dif?culty inherent in these processes is
due to the fact that in the isomerization of hy
50
drocarbon mixtures generally available compris
ing both normal hexane and methylcyclopentane
the proportion of methylcyclopentane initially
present which is converted to cyclohexane ex
' ceeds the proportion of normal hexane converted
‘to isohexane, thereby resulting in a progressive
increase of normal hexane concentration in the
unconverted portion of the charge recycled to
the reaction zone to further complicate the sep
aration problems encountered. It is thus clearly
methylcyclopentane and the alkyl cyclopentanes.
It has been suggested heretofore to- subject (i0 .' apparent that the advantages inherent in such
2,409,390
3
4
processes as available heretofore in even such
speci?c cases are limited.
tion of cyclopara?ins and particularly the cyclo
para?ins of hydroaromatic structure, these proc
Separation of cycloparaf?ns having more than
six carbon atoms to the molecule from the highly
complex hydrocarbon mixtures in which they are
esses also suffer from an inability to attain con
encountered presents even greater difficulties. In
these cases the problems encountered in attempt
matic structure to cyclopara?ins of hydroaro
version equal to or approximating equilibrium
conversions of cycloparal?ns of non-hydroaro
para?ins are in no Wise overcome by ?rst isomeriz
matic structure when effecting the separation
process under isomerizing conditions. Increasing
the time of contact between solvent and hydro
ing the hydrocarbon mixture as a whole under
isomerizing conditions resorted to heretofore.
Such methods do not provide a practical answer,
for example, to the production of hydrocarbons
carbons essential to the attainment of higher con
version rates results, as shown above, in the loss
of a substantial amount of cyclopara?ins due to
the increase in reaction rates of side reactions
ing to e?ect substantial separation of the cyclo
predominating in methylcyclohexane from the
converting cyclopara?‘lns to higher boiling mate
readily available hydrocarbon mixtures compris 15 rials.
ing the non-hydroaromatic cyclopara?ins having
It has now been found that separation of
seven carbon atoms to the molecule in admixture
cyclopara?ins from para?inic hydrocarbons ad
with open chain para?ins having seven and eight
mixed therewith is effected with even greater
e?iciency by distilling the cycloparaffin-contain
atoms to the molecule and having the same boil
ing range.
20 ing hydrocarbon mixture in the presence of a
In its broadest aspect the object of the present
countercurrent stream of preformed organo-metal
invention is to provide an improved process en
halide complex. By maintaining suitable isomer
abling the more efficient separation of cyclo
ization conditions in the extractive distillation
para?ins from hydrocarbon mixtures comprising
zone the cycloparaf?ns of non-hydroaromatic
cycloparaf?ns and open chain paraf?ns.
structure present in the hydrocarbon mixture
A more particular object of the invention is the
are converted to cycloparaf?ns of hydroaromatic
provision of a process enabling the more efficient
structure during the cyclopara?in separation.
separation of cyclopara?ins from hydrocarbon
Separation of the cycloparaf?ns from hydrocar
mixtures comprising cycloparaf?ns and open
bo-n mixtures comprising them by means of ex
chain para?lns under isomerizing conditions.
Another object of the invention is the provision
of a process enabling the more ei?cient separation
of cyclopara?ins from hydrocarbon fractions com
prising cycloparaf?ns and open chain para?ins
having substantially the same number of carbon
atoms to the molecule.
Another object of the invention is the provision
30 tractive distillation under hydrocarbon isomeriz
ing conditions in accordance with the process of
the invention enables the attainment of substan
tially equilibrium conversions of cyclopara?ins of
non-hydroaromatic structure to cycloparaf?ns of
hydroaromatic structure in the absence of any
substantial loss of cycloparaf?ns due to their con
version to higher boiling products, thereby pro
viding signal advantages over the liquid phase
extraction method as well as over other processes
separation of cyclopara?‘ins of non-hydroaromatic
structure from hydrocarbon mixtures comprising 40 available heretofore for the production of cyclo
para?ins of hydroaromatic structure.
cycloparaf?ns and open chain para?ins with si
In accordance with the process of the invention.
multaneous conversion during the separation of
the hydrocarbon charge comprising a mixture of
non-hydroaromatic cycloparaf?ns to hydro
aromatic cyclopara?ins.
cyclopara?ins and open chain para?ins such as,
of an improved process enabling the more e?icient
A further object of the invention is the pro
r for example, a naphthenic straight run gasoline
vision of an improved process for the more e?l
fraction optionally predominating in hydrocar
cient production of hydrocarbons predominating
bons having substantially the same number of
carbon atoms to the molecule, such as a hexane
or heptane fraction, is introduced into a distilla
tion zone comprising, for example, a fractional
distillation column. Into the upper part of the
column there is introduced a preformed organo
in cyclohexane from hydrocarbon fractions com
prising open chain hexanes and methylcyclo
pentane.
Still another object of the invention is the pro
vision of an improved process for the more e?i
cient production of methylcyclohexane from hy
drocarbon fractions comprising open chain paraf
?ns and cyclopara?ins of non-hydroaromatic
structure having seven carbon atoms to the mole
cule. Other objects and advantages of the in
vention will become apparent from the following
description thereof.
It is known that unsaturated hydrocarbons,
such as ole?ns and aromatic hydrocarbons, which
react readily with aluminum chloride are removed
from hydrocarbon mixtures containing them by
treatment with aluminum chloride. In copending
metal halide complex obtained by the interaction
of a metal halide of the Friedel-Crafts type and
i an organic compound, resulting in the contacting
of the upwardly rising hydrocarbon vapors with
a descending stream comprising hydrocarbon re
flux and organo-metal halide complex. The ratio
of the organo-metal halide solvent introduced into
the column to the hydrocarbon charge is main
tained suf?ciently high to assure a homogeneous
liquid phase in equilibrium with the vapor. Con
ditions within the column are controlled to result
in the production of overhead vapors comprising
application, Serial Number 538,192, ?led May 31,
1944, now Patent 2,382,445, of which the present
application is a continuation-in-part, it has been
shown that saturated hydrocarbons of cyclic
' paraf?nic hydrocarbons and a liquid bottom prod
structure comprising the cycloparaf?ns can be
zone wherein hydrocarbons comprising the cyclo
uct comprising organo-metal halide complex and
cycloparai?ns. Bottoms from the extractive dis»
tillation zone are passed to a solvent separating
separated efficiently by liquid phase extraction 70 para?ins are separated from the organo-metal
under suitable conditions with a preformed com
plex obtained by the interaction of a metal halide
of the Friedel-Crafts type and an organic com
pound. Though such liquid phase extraction re
sults in substantial improvement in the produc
halide solvent.
The cycloparaf?ns eliminated
from the complex separating zone are introduced
into a product separating zone wherein separation
of cyclopara?ins into fractions predominating in
7 cyclopara?'ins of particular composition is eifected,
2,409,890
6
‘Within column. ‘Lthe hydrocarbon mixture
charged thereto through line 6 is ‘subjected to frac
tional distillationrwith the aid of suitable heating
means comprising heater 9, closed heating coil 10
‘and; controlledintroduction of re?ux into the
The vapor overhead from‘ the extractive distil
lation column, comprising the para?inic. ‘hydro
carbons,-is passed through a condensing zone into
an accumulating. zone. ‘A. portion :of the con
densate is taken from the accumulating zone and
passed as re?ux to the distillation zone.
‘
upper part of the column.
‘ ‘
.
A preformed organo-metal halide complex is
introduced into the top of fractionatingcolumn
By maintaining suitable cyclopara?in isomeriz
ing conditions within the extractive distillation
zone, comprising the introduction of a hydrogen
‘I by means of valved line L2. The fluid organo
vinto the extractive distillation zone, and the
metal halide complex is prepared by‘ mixing a
metal halide of the'Friedel-Crafts type, for‘exam
maintenance'therein of ‘conditions de?ned more
ple, a halide of aluminum such as aluminum chlo
halide or a material‘ affording a hydrogen halide
ride and/or aluminum bromide with an organic
fully below, the isomeriz’ation of cyclopara?ins
compound under suitable conditions resulting in
such as, for example, the conversion of cycle
parflins of non-hydroaromatic structure to cyclo~ 15 the interaction of the'metal halide with. theor
ganic compound and/or decomposition-products
para?ins of hydroaromatic structure is accom
plished simultaneously with the extractive distil
lation operation.
‘
When the extractive ‘distillation zone is thus
maintained under cyclopara?ln isomerizing con
thereof. Suitable organic compounds with which
the metal halide may be combined under con
ditions resulting in the obtaining of a desired
20 organo-metal halide complex comprising,‘ for ex
ditions, vapor overhead eliminated therefrom and
ample, aromatic hydrocarbons such as benzene,
the hydrocarbons comprising cycloparaf?ns elimi
nated from the organo-metal halide complex‘so-l
matic kerosene extract; cyclic ole?ns such as
toluene; hydrocarbon fractions such as an arc
fractions comprising the hydrogen halide are
cyclohexene, cyclopentene, and alkyl derivatives
thereof; para?inic and ole?nic hydrocarbons of
straight or branched chain structure; phenols;
organic acids; ethers, etc. Of the suitable organo
metal halide complexes, those comprising the ‘alu
recycled to the extractive distillation zone.
minum chloride-hydrocarbon complex are some
vent separating zone are passed in separate
streams to‘independent stripping zones wherein
the hydrogen halide promoter admixed therewith
is separated as gaseous fractions.
The gaseous
’
In order to set forth more clearly the nature of 30
the invention it will be described herein in detail
what preferred.
‘
l
,
The rate of introduction of the organo-metal
halide complex into the column may vary consid
with reference to the attached drawing in which
erably within the scope of the invention. ‘The
the single ?gure represents a more or less dia
ratio of solvent introduced into the column to hy
grammatic elevational view of one form of appa
ratus suitable for executing the process of the 35 drocarbon is, however, maintained su?iciently
high to maintain a homogeneous liquid phase
in equilibrium with the vapors at all times. Rae
A hydrocarbon mixture of relatively wide boiling
tios of org‘ano-metal halide solvent to hydrocar
range comprising cycloparaf?ns and open chain
bon feed of from about 4:1 to about 30:1 have
para?ins such as, for example, a naphthenicgaso
line is forced by means of pump I through line 2 40 been found satisfactory. Higher or lower ratios
of solvent to hydrocarbon may, however, be em
into a feed fractionating zone. Suitable heating
ployed within the scope of the invention. Par
means such as, for example, a hydrocarbon ?uid
af?nic hydrocarbon reflux is introduced into the
heater or indirect heat‘ exchanger 3 is positioned
in line 2. ‘The feedfractionating zone is depicted
upper part of the column, preferably above the
point of introduction of the organo-metal halide
‘in the drawing by a single fractionator 5 for the
solvent by means of line l3. Conditions of tem
purpose of simplicity. It will be understood that
perature maintained within column 1' will, of
in actual practice more than one such fractionat'dr
course, vary in accordance with the nature of the
may be employed toeffect the desired feed frac
hydrocarbon mixture introduced therein. Condi
tionation. Within ‘feed fractionator 5 there is
separated a fraction of intermediate boiling
tions within the column are, however, at all times
carefully controlled to effect the separation of a
range. The fraction of intermediate boiling range
vapor fraction consisting predominantly of paraf
may comprise, for example, hydrocarbons having
?nic hydrocarbons from a liquid fraction consist
six atoms to the molecule, such as 'a hexane frac
ing predominantly of organo-meta'l halide com
' tion comprising open chain hexanes, methylcyclo
plex and cyclo-paraiiins.
pentane and cyclohexane. Although a hexane
Liquid bottoms comprising the organo-alumi
fraction is chosen in the present illustrative de
invention.
~
'
‘
'
i
‘
‘
num‘ chloride complex and cyclopara?ins are
scription it is to be understood that the inven
tion is in no Wise limited to the’ separation of a
hexane fraction‘as a fraction of intermediate boil
ing range. Thus, the intermediate boiling range
fraction may comprise hydrocarbons having seven
carbon atomsto the molecule; a hydrocarbon mix
ture of wider boiling range comprising both
valved line l5 and heat exchanging means l6 into
a complex separating zone. The complex sepa
rating zone may comprise a still l'l. "Within still
' Cs and C7 hydrocarbons, or a hydrocarbon mixture
Vapors comprising methylcyclopenta'neiand cyclo
comprising or predominating in‘ hydrocarbons
hexane are passed from still ll through line" l8
and cooler l9 into an accumulator 20. The cyclo
parar?ns maybe removed from accumulator 20
having more than ‘seven carbon atoms to the
molecule.
The hexane fraction is passed from fractionator
-5 through line 6 into an extractive distillation
The extractive distillation zone may com
" zone.
prise a fractionating column ‘I. A valved line
passed from the lower part of column 1 through
H the hydrocarbons comprising cycloparaf?ns are
distilled from the organo-metal halide complex.
through valved line ‘M as a ?nalproduct.
A
‘part of the cyclopara?ins is, howeverepreferably
passed through lines 23,, 24 and 25 into a fraction
ator 26. Within fractionator 26 a vapor fraction
comprising methylcyclopentane is separated from
a liquid fraction comprising clycohexane. ,The
4 is provided for the introduction of hydrocarbon
charge directly into line 6. The hydrocarbons so
. liquid fraction is eliminated from fractionator 26
introduced by means of line 4, may constitute a
part or all of the hydrocarbon charge to column ‘I. 75 through valved line 28 as a ?nal product. The
2,409,390
vapor-fraction is eliminated from fractionator 26
through valved line 29.
,
'
The vapor overhead from extractive distillation
column 1 comprising open chain hexanes is passed
through line 3| and cooler 32 into an accumulator
33. A portion of they para?lnic condensate is
passed from accumulator 33 through lines 34 and
B as re?ux into the upper part of fractionator 1.
8
Overhead comprising unconverted .methylcy
clopentane, eliminated from column 26 through
line 29, is recycled at least in part to extractive
distillation column ‘I, by means of lines 43 and
6, .or is subjected to the extractive distillation in
accordance with the invention in a separate ex
tractive distillation zone not shown in the draw
mg.
-
Although the separation of the organo-metal
Separation of cycloparaf?ns from the metal
halide solvent from cyclopara?ins is accomplished 10 halide hydrocarbon complex solvent, it has been
by ‘distillation in the above illustrative description
found, is facilitated by effecting such separation
of the invention, other means of effecting such
within still 1 in the presence of additionally in
separation may be resorted to. ' The complex may
troduced hydrogen halide. A valved line 45 is
be separated from cycloparaf?ns by scrubbing the
therefore provided to enable the passage of hy
mixture with a suitable hydrocarbon such as, .for
drogen chloridev from line 36 into line I5 carry
example, a low boiling-saturated hydrocarbon,
ing ‘liquid bottoms from extractive distillation
suchzas butane or pentane; as disclosed in copend
column 1 into still ll. In a further modi?cation
ing-application, Serial No. 538,893, ?led June 6,
of the invention hydrogen halide, for example,
.1944, now Patent 2,382,445.
hydrogen chloride, is introduced into still l'l
A particular advantage of the invention resides "-20 through line 45, but no hydrogen halide is in
in the ability to recover the naphthenic hydrocar
troduced into extractive distillation column 1.
bons of non-hydroaromatic structure, originally
Column 1 will then function as described above
present in the charge, in the form of naphthenic
to effect the separation of cyclopara?ins from
hydrocarbons of hydroaromatic structure. Thus,
para?ins in the absence of any substantial cyclo
in the treatment of a naphthenic hexane fraction
paraf?n isomerization, whereas in still I‘! isom
containing methylcyclopentane, maintenance of
erization of cyolopara?ins, for example, con
suitable .cycloparaf?n isomerizing conditions
version of cyclopara?ins of non-hydroaromatic
within column 1 enables the conversion of meth
structure to cyclopara?ins of hydroaromatic
ylcyclopentane to cyclohexane during the ex
structure will take place. Under these condi
tractive distillation operation. To attain these 30 tions still I’! will function as a cyclopara?in isom
objectives a hydrogen halide promoter such as,
for example, hydrogen chloride, or a material
affording the hydrogen halide under the condi
tions maintained in column 1, is introduced into
the lower part of the column through valved line
35 at a point below the introduction of the charge.
A part of the hydrogen chloride may be intro
duced directly into line 8 from line 36. The hy—
erizing zone.
Organo-aluminum chloride complex, substan
tially free of cycloparat?ns, is eliminated from
still I‘! through valved line 46 and introduced
into line l2, passing into the top of column ‘I.
The temperature of the recycled complex is ad
justed by suitable ‘means so that it is introduced
into column 1 at a temperature substantially
drogen chloride promoter is introduced at such a
equal to the temperature in column 1 at the point
rate as to maintain a concentration of- the hydro 40 of its introduction.
gen halide in the column in the range 01? from
Hydrocarbon mixtures comprising naphthenic
about 0.1 to about 2.0 and preferably from about
hydrocarbons often contain, in addition to open
0.1 to about 0.5 per cent by Weight of the hydro
chain para?ins, a certain amount of aromatic
carbon in the column.
hydrocarbons. Thus, the naphthenic hexane
When thus maintaining cyclopara?'in isomeriz 45 and/or heptane fractions will generally com
ing conditions within column ‘I, the vapor over
prise a certain amount of benzene and/or toluene.
head passing from extractive distillation column
This material may be removed from the charge
‘I through line 3| will contain hydrogen chloride.
by suitable pretreatments prior to introduction
The hydrocarbons comprising hydrogen chloride
into column 1. The organo-aluminum chloride
within accumulator 33-are forced through line
complex, it has been found, however, is far more
31 into a stripping column 38. The hydrogen
selective as a solvent for aromatic hydrocarbons
chloride thus separated in column 38 is passed
than for cyclopara?ins. Distillation within still
therefrom through lines M, 36 and 35 into col
I‘! of the liquid bottoms emanating from column
umn ‘I. ‘Make-up hydrogen chloride is intro
‘I under conditions effecting the separation of
duced into the system by means of valved line. ;
cyclopara?ins from the complex will generally
42. Para?inic hydrocarbons comprising open
result in a retention in the complex of at least
chain hexanes are eliminated from the lower part
a substantial amount of the aromatics originally
of stripping column 38, through valved line 44,
present in the charge. In a modi?cation of the
as a ?nal product.
invention, when the charge to the system com
Bottoms from extractive distillation column ‘I
prises aromatic hydrocarbons, at least a part of
will generally be free of any substantial amount
the complex eliminated from still I‘! is passed
of hydrogen chloride. vWhen, however, hydrogen
through line 48, containing heat exchanging
chloride is present in the hydrocarbons in ac
means 49, into a third distillation zone compris
cumulator 20, because, for example, of separate
ing, for example, still 50. Within still 50 the
complex, substantially free of cycloparaflins but
still containing aromatic hydrocarbons, which
hydrogen chloride introduction into still H as
described more fully below, the hydrocarbons con
taining hydrogen chloride are passed from ac
cumulator 20 through lines 23 and 39 into a
separate stripping column 40. Overhead con
in the treatment of naphthenic hexane fractions
will comprise benzene, is subjected to more drastic
distillation conditions to effect the separation of
taining hydrogen chloride is recycled from strip
substantially all of the benzene. The more
ping column 40, through lines 36 and 35, to ex
drastic conditions may be obtained by distilla
tractive distillation column 1. Cyclopara?‘ms
tion at a higher temperature by means of heat
comprising cyclohexane and unconverted methyl
input into heating means 49 and closed heating
cyclopentane are passed from stripping column
coil 5|, by prolonged residence time in still 50,
,40 through valved'line 25, into fractionator 26.
75. by use of subatmospheric pressure, by the in
2,409,390
10
troduction of stripping gases such as hydrogen,
from methylcyclopentane and cyclohexane is‘ ef
methane, ethane, nitrogen, etc., through valved
fected in the process of the invention. In the
distillation of a separate portion of the same full
hexane fraction utilized as charge‘ in the above
line 52, or hydrogen chloride through line 53, or
by any two or more of these expedients. Vapors.
comprising benzene are eliminated from still 50
example under substantially identical conditions
but in the absence of the hydrocarbon-aluminum
through valved line 54. Organo-aluminum chlo
ride complex, now free of any substantial amount
of benzene, is taken from still 50 through valved
chloride complex solvent, it was found that all of
the dimethylpentane content of the feed was
contained in the bottoms of the distillation col
line 55, and is recycled at least in part through
lines 56, 46 and [2 into the upper part of frac
tional distillation column ‘I.
_
,
umn.
'
1. The process for the separation of ‘cyclopar
af?ns comprising methylcyclopentane from a hy
drocarbon mixture containing said cyclopara?ins
in admixture with open chain para?ins having
substantially the same boiling range with simul
taneous conversion of methylcyclopentane to
oyclohexane during said separation which com
prises subjecting said hydrocarbon mixture to
The following examples are illustrative of the
isomerization of cyclopara?ins with simultaneous
separation of cycloparaihns from admixtures with
open chain para?ins in accordance with the proc
ess of the invention.
Example
‘In a series of separate operations, ‘portions of
a full range hexane fraction, obtained by frac
fractional distillation in a fractionating zone, in
Per cent by volume
troducing a preformed aluminum chloride-hydro
carbon complex into the upper part of the frac
tionating zone, introducing hydrogen chloride
into a lower part of the fractionating zone, there
_________________ __ 33
a by simultaneously converting methylcyclopentane
tional distillation of napthenic ‘ straight‘ run ~ gas
oline, and having the following composition:
Naphthenes:
Methylcyclopentane
'‘
We claim as our invention:
‘
Cyclohexane ________________________ __ 21
to cyclohexane and forming a vapor fraction pre
dominating in para?ins and a liquid fraction pre
Methylpentanes _____________________ __
dominating in aluminum chloride-hydrocarbon
1
Normal hexane ______________________ __ 34
complex and cycloparaf?ns comprising cyclohex
Dimethylpentanes ________ __‘ ______ _i____
ane, separately removing said vapor and liquid
fractions from the fractionating zone, and sep
Benzene
,
4
.
7
arating cycloparaf?ns comprising cyclohexane
were subjected to extractive distillation under
isomerizing conditions in a 40 bubble plate frac
from said liquid fraction. ,
‘
2. The process for the separation of cyclopar
tionating column. ‘Into the upper part of the _ af?ns comprising methylcyclopentane from a hy
column there was introduced a preformed hydro
drocarbon mixture containing said cyclopara?ins
carbon-aluminum chloride complex prepared from
in admixture with open chain para?‘ms having
equal parts of aluminum chloride and a kerosene
substantially the same boiling range with simul
extract having a boiling range of from 150°C. to
taneous conversion of methylcyclopentane‘ to
200° C. Hydrogen chloride Was‘introduced in con 40 cyclohexane during said separation which com
tinuous stream into the lower part of the extrac
prises subjecting said hydrocarbon mixture to
tion distillation column. Bottoms ‘from the ex;
fractional distillation in a fractionating zone, in
tractive distillation‘ column were passed into a
troducing a preformed aluminum halide-hydro
stripping column wherein separation of extracted
carbon complex into the upper part of the frac
hydrocarbons from complex ‘was accomplished.
tionating zone, introducing hydrogen halide into
Complex taken'from the bottom of the stripping 45 a lower part of the fractionating zone, thereby
column Was‘recycle‘d to the upper partvof the ex
simultaneously converting methylcyclopentane to
tra'ctive distillation column. The recycle stream
temperature, was adjusted to that within the
cyclohexane and forming a vapor fraction pre
dominating in para?ins and a liquid fraction pre
fractional distillation column at the point‘ of its
dominating in aluminum halide-hydrocarbon
introduction. Conditions of operation as well as 50 complex and cyclopara?ins comprising cyclohex
results obtained'are indicated in the following
table:
'
ane, separately removing said vapor and liquid
“
fractions from the fractionating zone and sep
arating cyclopara?ins comprising cyclohexane
Run No.
55 from said liquid fraction.
it
3. The process for the separation of cyclopar
af?ns comprising cyclopara?lns of non-hydro
1723
aromatic structure from a hydrocarbon mixture
Extractive distillation column:
_ _
containing said cyclopara?ins in admixture ‘with
‘
Plates above complex introduction _________ __
Plates above feed introduction _____________ __
6
28
60
hydrocarbon feed ___________ .__.;_ _________ ..
5.9
Volume percent alClircomplex in column__-_ .
92
1
Re?ux ratio at st1l1head_ ___________________ __
- H01 introduced-weight percent of hydro
carbon [eed ____ -_. ............. .r
.
-._
0 5
HOw.
Temperature of stripping column, ° 0
Results:
‘
.
»
l_
openchain para?ins having substantially the
same boiling range with simultaneous conver
sion of cyclopara?ins of non-hydroaromatic
structure to cycloparaf?ns of hydroaromatic
Volume ratio of AlOli-complex charged to
A
Volume percent of naphtlienes in stripper
structure during said separation which comprises
subjecting‘ said hydrocarbon mixture to a frac
tional distillation in a fractionating zone, intro
ducing a‘preformed aluminum halide-hydrocar
bon complex into the upper part of the fraction
Percent of dimethylpentanes in feed rejected
ating zone,‘ introducing av hydrogen halide into
overhead in extractive distillation column .45
70 a lower part of the fractionating zone, thereby
Oyclohcxane to methylcyclopentane, ratio
in extractive distillation column bottoms,
converting cycloparai?ns of non-hydroaromatic
82
100
percent of equilibrium .................... _
structure to cyclopara?ins of hydroaromatic
structurewhile forming a ‘vapor fraction predom
inating inparaf?ns and a liquid fraction predom
It is seen from the foregoing example that sub
stantial separation of even dimethylpentanes 75 inating in aluminum halide-hydrocarbon com
overhead?uzn'n: _____________________ __'_.
Percent of paraiilns in feed rejected overhead i
in extractive distillation column .......... __
79
71
‘
NaC)“Olaf»
2,409,390‘
12
11
plex in admixture with cycloparaifms comprising
cyclopara?ins of hydroaromatic structure, sep
arately removing said vapor and liquid fractions
carbon complex in admixture with cyclopara?ins
containing cyclohexane, and separating cyclo
paraf?ns comprising cyclohexane from said liquid
from the fractionating zone, and separating cyclo
parainns comprising cyclopara?‘ins of hydroaro
matic structure from said liquid fraction.
4. The process for the separation of cyclo
GI
fraction.
7. The process for the production of cyclo'par
a?ins of hydroaromatic structure from a hydro
carbon mixture containing cycioparairins com
para?ins comprising cyclopara?ins of non-hydro
prising
aromatic structure from a hydrocarbonv mixture
structure and open chain para?ins having sub
containing said cyclopara?ins in admixture with
open chain para?ins having substantially the
stantially the same boiling range which comprises
subjecting said hydrocarbon mixture to fractional
distillation in the presence of a preformed. alu
minum halidenhydrocarbon complex and hydro
same boiling range with simultaneous conversion
of cyclopara?ins of non-hydroaromatic structure
to cyclopara?ins of hydroaromatic structure dur
ing said separation which comprises subjecting
cyclopara?ins
of
non-hydroaromatic
gen halide, thereby simultaneously converting
cycloparaf?ns of non-hydroaromatic structure to
cyclopara?ins of hydroaromatic structure and
forming a vapor fraction comprising para?ins
and a liquid fraction comprising aluminum
halide-hydrocarbon complex and cyclopara?ins of
said hydrocarbon mixture to a fractional distilla
tion. in a fractionating zone, introducing a pre
formed. aluminum halide-containing complex- in
teraction, product obtained by the interaction of
an aluminum halide with an organic compound 20 hydroaromatic structure, and separating cyclo
into the upper part of the fractionating zone, in
paraf?ns of hydroaromatic structure from said
troducing a hydrogen halide into a lower part of
liquid‘ fraction.
the fractionating zone, thereby converting cyclo
8. The process for the production of cyclopar
paramns of non-hydroaromatic structure to cy
a?‘ins of hydroaromatic structure from a hydro
cloparaf?ns of hydroaromatic structure while 25 carbon mixture containing cyclopara?in‘s com
forming a Vapor fraction. predominating in- par
a?ins and av liquid fraction predominating in
prising
cyclopara?ins of non-hydroaromatic
structure and open chain para?ins having sub
organo-aluminum halide complex in admixture
stantially the same boiling range which comprises
with cyclopara?ins comprising cyclopara?ins of
subjecting said hydrocarbon mixture to fractional
hydroaromatic structure, separately removing 30 distillation in the‘presence of a hydrogen halide
said vapor, and liquid fractionsrfromthe fraction
and‘ a preformed metal halide-containing com
ating zone, and separating cyclopara?ins com
plex interaction product obtained by the interac
prising cyclopara?ins of hydroaromatic structure
tion of a metal halide of the Friedel-Crafts type
from, said liquid fraction.
and an organic compound, thereby simultaneous
_5. The process for the separation of cyclopar
af?ns, comprising. cyclopara?ins of‘ non-hydro
35
ly converting cycloparaffins of nonehydroaro
aromatic structure from a hydrocarbon mixture
matic structure to cycloparaf?ns of hydroaro
matic structure and. forming‘a vapor fraction
containing said cyclopara?ins in: admixture with
open chain para?ins having substantially the
comprising paraf?ns and a liquid fraction com
prising said metal halide-containing complex and
same boiling range with simultaneous conversion 40 cycloparaf?ns of hydroaromatic. structure, and
of cyclopara?ins‘ of non~hydroaromatic structure
separating cyclopara?ins of hydroaromatic struc
to cyclopara?ins of. hydroaromaticstructure dur
ture from said liquid fraction.
ing said separation which comprises subjecting
9. The process for separating cycloparai?ns
said hydrocarbon mixture toa fractionaldistilla
comprising cycloparai?ns of non-hydroaromatic‘
tion in. a fractionating zone, introducing a pre
45 structure from a hydrocarbon mixture containing
formed metal halideecontaining complex inter
said cycloparaf?ns in admixture with open chain
action. product obtained by. the interaction of a
paraf?ns having substantially the ‘same boiling
metal halide of the FriedelrCrafts type and an
range with simultaneous conversion of‘ cyjclopar
organic compound into the upper part of- the
a?ins of non-hydroaromatic structure to cyclo
fractionating zone, introducing a hydrogen halide 50 para?ins of hydroaromatic structure which ‘com
into a lower part of the fractionatingzone, there
prises subjecting said hydrocarbonv mixture to
by converting cycloparaf?ns of non-hydroaro
fractional distillation in a fractional distillation
matic structure to cyclopara?ins of‘ hydroaro
zone, introducing a preformed metal halide-con
matic structure while forming a, vapor fraction
taining complex interaction product obtained by
predominating in para?finsand a liquid fraction 55 the interaction of a metal halide of the Friedel
predominating in said metal halide-containing
Crafts type and an organic compound into the
complex in admixture with cycloparamns com
upper part of the fractional distillation zone, in
prising cycloparai?ns of hydroaromatic struc
troducing a hydrogen halide intoa lower part of
ture, separately removing said-vapor and. liquid
the fractional distillation zone, thereby simul
fractions from the fractionating. zone, and sep 60 taneously converting cycloparaf?ns of non-hy
arating cycloparaf?ns comprising cycloparaf?ns
droaromatic structure to cyclopara?ins of hydro
of hydroaromatic structure from: said liquid
aromatic structure and forming a vapor fraction
fraction.
predominating in paraf?ns in admixture with hy
6. The process for the production, of cyclo
hexane from a hydrocarbon mixture containing 65 drogen halide and a liquid fraction predominat
cycloparai?ns comprising methylcyclopentane
and open chain paraf?ns having substantially the
ing in said metal halide-containing complex in‘
admixture with cycloparaf?ns comprising cyclo
para?ins of hydroaromatic structure, separately
removing said vapor and liquidvfractions from the
tion in the presence of a preformed aluminum 70 fractionating zone, separating" cyclopara?ins
chloride-hydrocarbon complex and hydrogen
comprising cyclopara?ins or hydroaromatic
chloride, thereby simultaneously converting
structure from said liquid fraction, passing‘ said
methylcyclopentane to cyclohexane and forming
vapor fraction from said fractionating zone to
_ same boiling range which comprisessubjecting
said hydrocarbon mixture to fractional distilla
a vapor fraction comprising para?ins and a liquid
a stripping zone, separating a; gaseous fraction
fraction comprising aluminum chloride-hydro+ 75 comprising‘ hydrogen ‘halide inv said’v stripping
2,409,390
14
zone, and passing said gaseous fraction from said
stripping zone to the fractionating zone.
10. The process for the separation of cyclo
para?‘ins from a hydrocarbon mixture compris
by the interaction of a metal halide of the Fried
el-Crafts type and an organic compound, thereby
isomerizing said cyclopara?in to a cyclopara?in
of different molecular structure having the same
number of carbon atoms to the molecule and con
ing an isomerizable cycloparamn having at ‘least
taining at least ?ve carbon atoms in the ring
six carbon atoms to the molecule and containing
while simultaneously forming a vapor fraction
at least ?ve carbon atoms in the ring in admix
comprising para?ins and a liquid fraction com
ture with open chain paraf?ns having substan
prising said metal halide-containing complex in
tially the same boiling range while simultane
ously isomerizing said cyclopara?in, which com 10 admixture with said isomerized cyclopara?in, and
prises subjecting said hydrocarbon mixture to
extractive distillation in the presence of a hy
drogen halide and a preformed metal halide
containing complex interaction product obtained
separating cycloparaf?ns comprising said isomer
ized cycloparaf?n from said liquid fraction.
WILLIAM ‘E. ROSS.
PHILIP PEZZAGLIA.
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